Device for the injection of gases into the feed system of an internal combustion engine

ABSTRACT

A device for the injection of secondary gases into the conduit for the intake of the gaseous fuel mixture of an internal combustion engine, comprising a nozzle mounted in said conduit the upstream mouth of which joins the said conduit in which it fits, and the downstream mouth of which is located in the said conduit with a certain clearance, forming a free annular space between said nozzle and said conduit, and duct for the supply of the said secondary gases, opening into said annular space, and communicating with a supply source of said secondary gases.

United States Patent Chavant 51 Aug. 1,1972

[54] DEVICE FOR THE INJECTION OF GASES INTO THE FEED SYSTEM OF AN INTERNAL COMBUSTION ENGINE [72] Inventor: Claude Chavant, lssy-Les Moulineaux, France [73] Assignee: Chrysler France [22] Filed: March 30, 1970 [21] App]. No.: 23,835

[52] U.S. Cl. ..123/l19A 51 Int. Cl ..F02m 25/06 [58] Field ofSearch ..123/119.A

[56] References Cited UNITED STATES PATENTS 1,539,126 5/1925 Link ..123/119A 2,421,406 6/1947 Bicknell 123/ 1 19 A 1,766,677 6/1930 Moore ..123/l19 A 1,768,853 7/1930 Moore ..l23/ll9A 1,793,554 2/1931 Moore ..l23/119 A FOREIGN PATENTS OR APPLICATIONS 1,019,378 1/1953 France ..l23/1l9 A 181,618 l/1905 Germany ..l23/l19A Primary ExaminerWendell E. Burns Att0rneySteinberg & Blake [5 7] ABSTRACT A device for the injection of secondary gases into the conduit for the intake of the gaseous fuel mixture of an internal combustion engine, comprising a nozzle mounted in said conduit the upstream mouth of which joins the said conduit in which it fits, and the downstream mouth of which is located in the said conduit with a certain clearance, forming a free annular space between said nozzle and said conduit, and duct for the supply of the said secondary gases, opening into said annular space, and communicating with a supply source of said secondary gases.

7 Claims, 3 Drawing Figures DEVICE FOR THE INJECTION OF GASES INTO THE FEED SYSTEM OF AN INTERNAL COMBUSTION ENGINE The present invention has essentially for its object a device for the injection of secondary gases, in particular inert gases, into the fuel feed system of an internal combustion engine. 1

In modern high compression rate and high specific output engines, the maximum combustion temperatures amply exceed the critical threshold of formation of nitrogen oxides. It has been suggested, in order to reduce this formation, which is detrimental, to introduce, through the normal intake system of the engine, inert gases which add to the gaseous air-fuel mixture. In this case, a certain amount of non-combustive inert gases is taken from the exhaust gases and re-injected into the carburetter after having been more or less cooled. In a device already known, the inert gases reach the carburetter, generally of the variable-Venturi type, through a simple pipe opening downstream of the said variable Venturi, and this, owing to the mechanical regulation of the said carburetters, does not lead to any disturbance in the carburetion. Unfortunately, in carburetters provided with pneumatic richness regulation, high-speed injection of addition gases by this method creates disturbances in the fields of pressure at the level of the nozzle and affects the richness regulation device according to no foreseeable law.

The invention has for its object a device which is both simple and effective, enabling in particular to use exhaust gases as additional inert gases, the supplementary injection of these additional gases into the feed system of the engine taking place without any disturbance in the fields of pressure in the feed system, the said device thus being, in particular, adapted to be used in carburetters provided with pneumatic richness regulation.

The device according to the invention enabling to attain this end is characterized in particular in that in the conduit for the intake of the gaseous fuel mixture into the engine is mounted a nozzle, the upstream mouth of which joins the said conduit in which it fits, and the downstream mouth of which is located in the conduit with a certain clearance, a duct of the like for the supply of the said secondary gases opening into the annular space comprised between the said nozzle and the said conduit.

Owing to this arrangement, a regular secondary gas injection is obtained wherein possible disturbances have no effect upon the feeding of the engine and do not affect the operation of the carburetter.

The invention will be better understood and other objects, characteristics and advantages thereof will appear as the following description. proceeds, with reference to the appended drawing given solely by way of example illustrating one form of embodiment of the invention and wherein:

FIG. I is a longitudinal sectional view of an injection device according to the invention;

FIGS. 2 and 3 show diagrammatically, to a smaller scale, transverse sectional views of two arrangements of the additional gas supply system.

According to the form of embodiment illustrated diagrammatically in FIG. 1, a conduit conveys the combustible gaseous mixture proceeding from the carburetter and circulating according to the arrow F in the direction of the cylinders of an internal combustion engine (not shown). At 11 there is shown the butterfly or throttle valve for the regulation of the intake flow.

According to the invention, in the conduit 10, therefore downstream of the gasoline or petrol injection ports of the carburetter (not shown), is mounted on a nozzle Venturi shaped tube or 12, the upstream mouth or inlet end 13 of which fits in an joins the conduit 10, for instance by being welded as shown at 14. The main intake of the gases flowing in the direction of the arrow F therefore follows the path through the interior of the nozzle 12 and issues again from the latter into the conduit 10 after having passed through the downstream outlet end or mouth 15 of the nozzle. The mouth 15 is located at a certain distance e from the conduit 10, so that between the nozzle 12 and the conduit 10 there is formed an annular space 16. Thus, the conduit 10 serves to direct the combustible mixture through the Venturi-shaped tube 12 which is fixed to the inner surface of the conduit 10 only at the upstream end of the tube 12 along the edge of the latter which defines the inlet 13. The space 16 which is defined between the exterior surface of the tube 12 and the interior surface of the conduit 10 has its maximum width around the throat of the Venturi-shaped tube 12 at an intermediate region spaced from the opposed ends of the tube 12, and this space 16 gradually diminishes in width from this intermediate region where the throat of the Venturi-shaped tube is located toward the opposed ends of the tube 12.

It is into this intermediate zone of the space 16 where the latter has its maximum width that the secondary gases, for instance inert gases derived from the exhaust gas system are conveyed for instance through two conduits l7, 18. These secondary gases circulating in the direction of the arrow f flow into the conduit 10 downstream of the inlet end of the nozzle. Advantageously, the conduits 17, 18 are located substantially at the level of the throat 19 of the nozzle. The conduits 17, 18 form a supply means communicating with the space 16 through the conduit 10 and having an outlet extending axially of the conduit 10 through a given distance equal to the diameter of each of the conduits 17, 18, this outlet opening into the intermediate zone of the space 16 for supplying exhaust gas thereto. This space 16 extends upstream of the outlet of the supply means 17, 18, through a substantial distance which is greater than the given distance axially of conduit 10 corresponding to the diameter of each of the conduits 17, 18, and in the same way the space 16 extends downstream of the supply means l7, 18 also through a substantial distance which is substantially greater than the given distance axially of conduit 10 which corresponds to the thickness or diameter of each of the conduits l7, 18. In this way the exhaust gases introduced through the supply means into the intermediate zone of the space 16 can expand in an upstream direction through the inlet end 13 of the tube or nozzle 12, and also the exhaust gases can flow in a downstream direction from the intermediate zone of space 16 through the gap between the downstream end 15 of tube 12 and the inner surface of the conduit 10. It will be noted from FIG. 1 that the supply means 17, 18 is situated substantially midway between the opposed upstream and downstream ends of the space 16. The

nozzle 12 is a conventional nozzle which is substantially in the shape of a hyperboloid of revolution or the like. Thus, the conduits 17 and 18 form a supply means for supplying exhaust gases into the space 16 defined between the tube 12 and the conduit at the intermediate zone of this space where it has its greatest width so that the gases not only can flow in the downstream direction toward the gap e defined between the outlet end 15 of the tube 12 and the conduit'l0 but also these gases can expand in an upstream direction in the space 16 toward the inlet end 13.

The layered stream of the gases issuing from the device is then substantially composed of a central jet of carburetted mixture G and an annular peripheral stream of additional gases g.

As already mentioned hereabove, such an intake of secondary gases enables to lower the nitrogen oxide content of the fuel gases and to improve the operation of the engine without disturbing the feed system, in particular where the carburetter used is of the pneumatic regulation type.

In addition to the aforementioned advantages, it is possible, by cooling more or less the recycled inert gases taken from the exhaust gases, to reduce the defrosting of the carburetter, especially in cold weather or upon starting, to correlatively reduce condensation at the level of the intake body pit. In addition, the atomization of the gasoline is improved.

The additional injection gases may either by conveyed into the annular space 16 in such a manner that the injection will take place substantially without rotation about the axis of the intake conduit, as diagrammatized in FIG. 2, or injected into the said space so as to ensure a rotation of the peripheral stream resulting in a certain mechanical effect of atomization and mixing of the mixture, as diagrammatized in FIG. 3, where the angle a between the conduits l7 and 18 and a line extending in a radial direction is illustrated.

This last structure of the swirl chamber shown in FIG. 3 is interesting because it has the potential of retarding exhaust recirculation at wide open throttle, which is a desirable condition.

It will be noted that because the tube 12 is of a substantially uniform wall thickness and is fixed only at its inlet end 13 to the inner surface of the conduit 10, the space 16 is free of any obstructions and the exhaust gases can flow in a smooth, controlled manner in the space 16 engaging only the inner cylindrical surface of the conduit 10 and the exterior gradually tapering surface of the tube 12.

Of course, the invention is by no means limited to the form of embodiment described and illustrated, which has been given by way of example only. In particular, it comprises all the means constituting technical equivalents to the means described as well as their combinations, should the latter be carried out according to the spirit of the invention.

What is claimed is:

1. In an internal combustion engine, an elongated conduit for directing a fuel-air mixture from a carburetter to an intake of the engine, an elongated tube of Venturi-shaped configuration coaxially situated within said conduit and having an upstream inlet end and a downstream outlet end, said tube having a substantially uniform all thickn s a d bein lxed nl t its stream in et end to t e iiiner su ace 0? sti l conciiiit its downstream outlet end a relatively narrow gap with the interior surface of said conduit and said tube also defining with the interior surface of said conduit an elongated annular space which has a maximum width at an intermediate zone of said space surrounding a throat region of said tube with said space gradually diminishing in width from said intermediate zone in the upstream and downstream directions respectively toward said inlet end of said tube and said gap, said space being closed at said inlet end of said tube so that it communicates with the interior of said conduit only through said gap, and supply means communicating trough said conduit with said space and having an outlet occupying a given distance axially of said conduit opening into the intermediate zone of said space for supplying exhaust gases thereto, said space extending upstream of said outlet through a substantial distance which is substantially greater than said given distance as well as dOwnstream of said outlet also through a substantial distance which is substantially greater than said given distance, so that exhaust gases supplied to said space by said supply means can expand in an upstream direction toward said inlet end of said tube in the interior of said space and flow in a downstream direction from said intermediate zone through said gap into contact with the mixture issuing through the downstream outlet end of said tube.

2. The combination of claim 1 and wherein said supply means includes at least one additional conduit communicating through an opening of said first-named conduit with said intermediate zone.

3. The combination of claim 2 and wherein said one additional conduit extends non-radially with respect to the common axis of said tube and first-named conduit so that the exhaust gases introduced through said supply means have a swirling motion in said space.

4. The combination of claim 3 and wherein there are a pair of said additional conduits respectively communicating with said intermediate zone of said space at diametrically opposed portions of said first-named conduit.

5. The combination of claim 1 and wherein a throttle valve is situated in said conduit downstream of and adjacent to the outlet end of said tube.

6. The combination of claim 1 and wherein said supply means includes a pair of diametrically opposed supply conduits extending along a straight line perpendicular to the common axis of said tube and first-named conduit and communicating through diametrically opposed openings of the latter with said intermediate zone.

7. The combination of claim 1 and wherein said supply means is situated substantially midway between opposed ends of said space.

- UNITED STATES PATENT OFFICE v CERTIFICATE OF CORRECTION Patent NO; 3,680,534 D t Auqustj..1972

Inventor s) QLAUDE YCHAVANT It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

No reference is madeto Foreign Application Priority Data which should be --April 3, 1969 France. .69l027l--.

Signed and sealed this 1st day of May 1973.

(SEAL) fattest:

EDNM-LD M. FLETCHER, JR. ROBERT GOTT'SCH'X LK Attesting Officer Commissioner of Patents FORM PO-105O (10-59) USCOMM-DC 60376-P59 Q U. 5 GOVERNMENT PRINTING OFFICE: 1969 O-36S33l. I 

1. In an internal combustion engine, an elongated conduit for directing a fuel-air mixture from a carburetter to an intake of the engine, an elongated tube of Venturi-shaped configuration coaxially situated within said conduit and having an upstream inlet end and a downstream outlet end, said tube having a substantially uniform wall thickness and being fixed only at its upstream inlet end to the inner surface of said conduit along the entire peripheral edge of said tube at said upstream inlet end thereof so that the mixture is directed by said conduit through said tube, the latter defining at its downstream outlet end a relatively narrow gap with the interior surface of said conduit and said tube also defining with the interior surface of said conduit an elongated annular space which has a maximum width at an intermediate zone of said space surrounding a throat region of said tube with said space gradually diminishing in width from said intermediate zone in the upstream and downstream directions respectively toward said inlet end of said tube and said gap, said space being closed at said inlet end of said tube so that it communicates with the interior of said conduit only through said gap, and supply means communicating trough said conduit With said space and having an outlet occupying a given distance axially of said conduit opening into the intermediate zone of said space for supplying exhaust gases thereto, said space extending upstream of said outlet through a substantial distance which is substantially greater than said given distance as well as dOwnstream of said outlet also through a substantial distance which is substantially greater than said given distance, so that exhaust gases supplied to said space by said supply means can expand in an upstream direction toward said inlet end of said tube in the interior of said space and flow in a downstream direction from said intermediate zone through said gap into contact with the mixture issuing through the downstream outlet end of said tube.
 2. The combination of claim 1 and wherein said supply means includes at least one additional conduit communicating through an opening of said first-named conduit with said intermediate zone.
 3. The combination of claim 2 and wherein said one additional conduit extends non-radially with respect to the common axis of said tube and first-named conduit so that the exhaust gases introduced through said supply means have a swirling motion in said space.
 4. The combination of claim 3 and wherein there are a pair of said additional conduits respectively communicating with said intermediate zone of said space at diametrically opposed portions of said first-named conduit.
 5. The combination of claim 1 and wherein a throttle valve is situated in said conduit downstream of and adjacent to the outlet end of said tube.
 6. The combination of claim 1 and wherein said supply means includes a pair of diametrically opposed supply conduits extending along a straight line perpendicular to the common axis of said tube and first-named conduit and communicating through diametrically opposed openings of the latter with said intermediate zone.
 7. The combination of claim 1 and wherein said supply means is situated substantially midway between opposed ends of said space. 